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Carbon-fibre composite transmission tunnel key element of lightweight design of Mercedes-Benz SLS AMG E-Cell
19 September 2011

On display in Frankfurt. The transmission tunnel made out of lightweight carbon-fibre composite material (CFRP) is structurally integrated into the aluminium body shell and firmly bonded with it. Click to enlarge.
A key element in the lightweight design of the Mercedes-Benz SLS AMG E-Cell electric vehicle (earlier post) is a transmission tunnel made out of lightweight carbon-fibre composite material (CFRP), which is structurally integrated into the aluminium body shell and firmly bonded with it. The high-strength and stiff CFRP component helps to reduce weight, while also serving as a monocoque housing for the battery modules.

The carbon-fibre battery monocoque in the SLS AMG E-CELL forms an integral part of the body shell and acts as the vehicle?s ?spine?.

The advantages of carbon composite materials were specifically exploited by the AMG engineers in its design. These include their high strength, which makes it possible to create extremely rigid structures in terms of torsion and bending, excellent crash performance and low weight.

CFRP components are up to 50% lighter than comparable steel ones, yet retain the same level of stability. Compared with aluminium, the weight saving is still around 30%, while the material is considerably thinner. The advantages in terms of weight achieved through the carbon-fibre battery monocoque are reflected in the agility of the SLS AMG E-CELL and, in conjunction with the highly innovative wheel-selective four-wheel drive system, ensure driving enjoyment.

The carbon-fibre battery monocoque is, in addition, conceived as a zero intrusion cell in order to meet the very highest expectations in terms of crash safety. It protects the battery modules inside the vehicle from deformation or damage in the event of a crash.

Through their experience with the SLR, the vehicles in the AMG Black Series and in motorsport, Mercedes-Benz and AMG have accumulated more than 10 years of expertise in working with carbon-fibre materials. AMG currently makes the propshaft for the SLS AMG, for example, in carbon-fibre. On the SLS Roadster, the supporting structure for the draught-stop is made as standard as a carbon sandwich structure. This component, with extremely short cycle times in an industrially oriented manufacturing process, already demonstrates what will be possible in the future.

CFRP components also play an important role in Mercedes-Benz and AMG?s lightweight design strategy for the future; the proportion of high-strength steels, aluminium and fibre-reinforced plastics is set to increase significantly in the future. The body shell weight of all Mercedes-Benz vehicles should fall by 10% compared with their predecessors.

The company says that the full-aluminium body shell of the SLS AMG shows the way for future model ranges.

http://www.greencarcongress.com/2011/09/cftunnel-20110919.html